Members of the faculties of the School of Medicine and the Division of Macromolecular Science, School of Engineering, have coordinated their resources for studies on the mechanisms and consequences of aging. This is being accomplished by studying non-renewable macromolecules (collagen, noncollagenous proteins, bone and muscle) physically via mechanical measurements at a macroscopic level and dynamic mechanical measurements at ultramicroscopic levels, physiologically via metabolic studies in acutely labeled and prelabeled animals, and chemically via the isolation and characterization of intramolecular and intermolecular crosslinkages. The purpose of the coordinated studies is to characterize physically, chemically, and metabolically the properties of non-renewable macromolecules as a function of age at the molecular and supramolecular levels.